Determination of the optical properties of anisotropic biological media using an isotropic diffusion model

We investigated the anisotropic light propagation in biological tissue in the steady-state and time domains. Monte Carlo simulations performed for tissue that consists of aligned cylindrical and of spherical scatterers show that the steady-state and time-resolved reflectance depends strongly on the measurement direction relative to the alignment of the cylinder axis. We examined the determination of the optical properties using an isotropic diffusion model and found that in the time domain, in contrast to steady-state spatiallyresolved reflectance measurements, the obtained absorption coefficient does not depend on the measurement direction and is close to the true value. Contrarily, the derived reduced scattering coefficient depends strongly on the measurement direction in both domains. Measurements of the steady-state and time-resolved reflectance from bovine tendon confirmed the theoretical findings.